The upper reaction shows how a transaminase combines with a glutamine residue, releasing ammonia, and then the combination reacts with the amine group of a lysine residue of another protein, setting the enzyme free again.

Transglutaminases form extensively cross-linked, generally insoluble protein polymers. These biological polymers are indispensable for an organism to create barriers and stable structures. Examples are blood clots (coagulation factor XIII), as well as skin and hair. The catalytic reaction is generally viewed as being irreversible, and must be closely monitored through extensive control mechanisms.[2]

A collection of the transglutaminase substrate proteins and interaction partners is accessible in the TRANSDAB database.

Recent research indicates that sufferers from neurological diseases like Huntington's[7] and Parkinson's[8] may have unusually high levels of one type of transglutaminase, tissue transglutaminase. It is hypothesized that tissue transglutaminase may be involved in the formation of the protein aggregates that causes Huntington's disease, although it is most likely not required.[2][9]

Transglutaminase can be used as a binding agent to improve the texture of protein-rich foods such as surimi or ham.[11]

So-called "Meat glue" made from bovine and porcine sources was banned throughout the European Union as a food additive in 2010.[12] Transglutaminase remains allowed and is not required to be declared, as it is considered a processing aid and not an additive which remains present in the final product.

Transglutaminase is also used in molecular gastronomy to meld new textures with existing tastes. Besides these mainstream uses, transglutaminase has been used to create some unusual foods. British chef Heston Blumenthal is credited with the introduction of transglutaminase into modern cooking.